1. Field of the Invention
The present invention relates generally to integrated circuits, and more particularly to integrated circuit fabrication processes and structures.
2. Description of the Background Art
The speed at which a signal is propagated in an integrated circuit is limited by the delay through the metal line carrying the signal. This delay, commonly known as “RC delay,” is determined by the product of the resistance (R) and capacitance (C) of the metal line. Reducing the resistance and/or capacitance of a metal line lowers its RC delay and increases signal propagation speed. Thus, reducing the RC delay of metal lines plays a major role in making integrated circuits run faster.